Temperature-independent verifying of structural integrity of materials using electrical properties

Abstract

Systems and methods for detecting a crack or defect in a material are described. An example method may include determining, by a computing device, for each respective adjacent pair of electrodes of a plurality of electrodes electrically coupled to the material, a respective electrode pair voltage. The method also may include determining, by the computing device, for each respective adjacent pair of electrodes, a respective temperature-corrected electrode pair value based on the respective electrode pair voltage and at least one of a respective control voltage associated with the respective adjacent pair of electrodes or a temperature correction factor. The method may further include determining, by the computing device, whether the material includes a crack or defect based on the plurality of respective temperature-corrected electrode pair values.

What is claimed is: 
     
       1. A method for determining whether a material includes a defect, the method comprising:
 controlling, by a computing device, an electrical signal source to apply an electrical signal to the material via a pair of drive electrodes, the pair of drive electrodes being included in a plurality of electrodes electrically coupled to the material, wherein all remaining electrodes of the plurality of electrodes other than the pair of drive electrode form respective adjacent pairs of measurement electrodes; 
 determining, by the computing device, for each respective adjacent pair of measurement electrodes of the plurality of electrodes electrically coupled to the material,
 a respective measurement electrode pair voltage, 
 a temperature correction factor based on a relationship between the respective measurement electrode pair voltage and a temperature at which the respective electrode pair voltage is measured; 
 a respective temperature-corrected measurement electrode pair voltage by applying the temperature correction factor to the respective measurement electrode pair voltage, and 
 a respective ratio between the respective temperature-corrected measurement electrode pair voltage and a control voltage associated with the respective adjacent pair of measurement electrodes; 
 
 determining, by the computing device, an average of the respective ratios; 
 subtracting, by the computing device, the average of the respective ratios from each respective ratio to determine a plurality of respective ratio differences; and 
 determining, by the computing device, that the material includes the defect based on the plurality of respective ratio differences. 
 
     
     
       2. The method of  claim 1 , wherein the electrical signal comprises at least one of a voltage signal or a current signal. 
     
     
       3. The method of  claim 1 , wherein determining that the material includes the defect based on the plurality of respective ratio differences comprises identifying, by the computing device, at least one outlier ratio difference from the plurality of respective ratio differences based on the at least one outlier ratio difference having a higher ratio difference than a remainder of the plurality of respective ratio differences. 
     
     
       4. The method of  claim 1 , wherein the material comprises an electrically conductive material or an electrically semiconductive material. 
     
     
       5. The method of  claim 1 , wherein the material comprises a ceramic. 
     
     
       6. The method of  claim 1 , wherein the control voltage is measured at a different temperature than the temperature at which the respective measurement electrode pair voltages are measured. 
     
     
       7. The method of  claim 1 , wherein the defect is a crack in the material. 
     
     
       8. A system for determining whether a material includes a defect, the system comprising:
 the material; 
 a plurality of electrodes electrically coupled to the material, wherein the plurality of electrodes includes a pair of drive electrodes, and wherein all remaining electrodes of the plurality of electrodes other than the pair of drive electrode form respective adjacent pairs of measurement electrodes; 
 an electrical signal source; and 
 a computing device configured to:
 control the electrical signal source to apply an electrical signal to a pair of drive electrodes included in the plurality of electrodes; 
 determine, for each respective adjacent pair of measurement electrodes of the plurality of electrodes electrically coupled to the material, 
 a respective measurement electrode pair voltage, 
 a temperature correction factor based on a relationship between the respective measurement electrode pair voltage and a temperature at which the respective electrode pair voltage is measured, 
 a respective temperature-corrected measurement electrode pair voltage by applying the temperature correction factor to the respective measurement electrode pair voltage, and 
 a respective ratio between the respective temperature-corrected measurement electrode pair voltage and a control voltage associated with the respective adjacent pair of measurement electrodes; 
 
 determine an average of the respective ratios; 
 subtract the average of the respective ratios from each respective ratio to determine a plurality of respective ratio differences; and 
 determine whether the material includes the defect based on the plurality of respective ratio differences. 
 
     
     
       9. The system of  claim 8 , wherein to determine whether the material includes the defect based on the plurality of respective ratio differences, the computing device is configured to identify at least one outlier ratio difference in the plurality of respective ratio differences based on the at least one outlier ratio difference having a higher respective ratio difference than a remainder of the plurality of respective ratio differences. 
     
     
       10. The system of  claim 9 , wherein the material comprises an electrically conductive material or an electrically semiconductive material. 
     
     
       11. The system of  claim 9 , wherein the material comprises a ceramic. 
     
     
       12. The system of  claim 8 , wherein the control voltage is measured at a different temperature than the temperature at which the respective measurement electrode pair voltages are measured. 
     
     
       13. The system of  claim 8 , wherein the defect is a crack in the material. 
     
     
       14. The system of  claim 12 , wherein the temperature correction factor is determined based on experimental data using the material. 
     
     
       15. The system of  claim 12 , wherein to determine the temperature correction factor, the computing device is configured to retrieve the temperature correction factor from a lookup table (LUT) that includes data based on the temperature at which the respective measurement electrode pair voltages are measured and the different temperature at which the control voltage is measured. 
     
     
       16. A non-transitory computer readable storage medium encoded with instructions that, when executed, cause one or more processors of a computing device to:
 control an electrical signal source to apply, via pair of drive electrodes, an electrical signal to a material, the pair of drive electrodes being included in a plurality of electrodes electrically coupled to the material, wherein all remaining electrodes of the plurality of electrodes other than the pair of drive electrode form respective adjacent pairs of measurement electrodes; 
 determine, for each respective adjacent pair of measurement electrodes of the plurality of electrodes electrically coupled to the material, 
 a respective measurement electrode pair voltage, 
 a temperature correction factor based on a relationship between the respective measurement electrode pair voltage and a temperature at which the respective electrode pair voltage is measured; 
 a respective temperature-corrected measurement electrode pair voltage by applying the temperature correction factor to the respective measurement electrode pair voltage, and 
 a respective ratio between the respective temperature-corrected measurement electrode pair voltage and a control voltage associated with the respective adjacent pair of measurement electrodes; 
 determine an average of the respective ratios; 
 subtract the average of the respective ratios from each respective ratio to determine a plurality of respective ratio differences; and 
 determine whether the material includes a defect based on the plurality of respective ratio differences. 
 
     
     
       17. The non-transitory computer readable storage medium of  claim 16 , wherein the instructions that, when executed, cause the one or more processors of the computing device to determine whether the material includes the defect based on the plurality of respective ratio differences comprise instructions that, when executed, cause the one or more processors of the computing device to identify at least one outlier ratio difference in the plurality of respective ratio differences based on the outlier ratio difference having a higher respective ratio difference than a remainder of the plurality of respective ratio differences. 
     
     
       18. The non-transitory computer readable storage medium of  claim 16 , wherein the defect is a crack in the material.